It is well known to produce laminated molded products, such as interior trim components for motor vehicles, from raw material blanks or webs or mats of multi-layered raw material, for example including thermoplastic fibers that serve as a thermoplastic meltable adhesive and matrix, as well as other fibers serving as a reinforcement or filler. A great variety of different methods and apparatuses for molding such a multi-layered raw material to produce a molded laminated product are also known in the art. For example, such known methods and apparatuses are disclosed in U.S. Pat. No. 6,749,794, U.S. Pat. No. 6,524,510, U.S. Pat. No. 6,287,678, U.S. Pat. No. 6,214,157, and many others.
The above mentioned methods and apparatuses are typically used especially for producing interior trim components, such as door panels and inserts, dashboards and dashboard inserts, consoles, headliners, parcel shelves and the like, for motor vehicles. Such trim components are generally produced by laminating, molding and cutting a laminated sandwich-type raw material blank formed of multiple layers, for example including a decorate cover sheet, a foam layer, and a structural carrier or substrate layer. The molding process involves heating the raw material and then deforming the heated and softened raw material in a mold apparatus under the required pressure, whereby the several layers of material are laminated and bonded with one another and molded into the desired three-dimensional contoured configuration. The lamination bonding can be achieved using an additional adhesive, or by using thermoplastic fibers of the raw material blank as a hot-melt adhesive. The processing temperatures for the molding processes are typically around 200° C.
The substrate or carrier layer may initially include thermoplastic fibers, for example of polypropylene, forming the matrix and hot-melt adhesive of the substrate, as well as reinforcing or filler fibers, such as preferably natural fibers or other non-melting fibers. For example, these reinforcing fibers can be synthetic plastic fibers, such as polyester fibers, that do not melt or only melt at temperatures greater than the arising process temperatures. The other layers such as a foam layer and/or a decorative cover layer may comprise any conventionally known or future developed materials typically used in the field of this invention. The substrate or carrier layer may also comprise any conventionally known or future developed materials suitable in the field of this invention. The present invention is applicable to the molding of sheet-like or web-like raw materials, or raw material blanks, regardless of the particular material composition or the number of layers thereof.
The conventionally known apparatuses for carrying out the molding of such a laminated sandwich-type raw material blank typically include a machine frame carrying at least an upper mold tool and a lower mold tool that are driven by drive elements such as piston-cylinder devices, so that the upper and lower mold tools are movable relative to each other, and thus form a mold that can be opened and closed. The conventional apparatuses typically further include a control arrangement for controlling the drive elements for moving the upper and lower mold tools relative to each other. Still further, the conventional apparatuses typically include a raw material transport arrangement that grasps, carries and transports a raw material blank to a position between the upper and lower mold tools, as well as a clamping frame or slip frame that takes over the raw material blank from the material transport arrangement and holds the raw material blank in the proper position between the upper and lower mold tools while the molding process is carried out.
Particularly, the slip frame frictionally holds a surplus edge rim of the raw material blank protruding laterally outwardly from the edge of the mold. The slip frame holds the surplus edge rim with a sufficient clamping force to support and hold the raw material blank in position, while still allowing the raw material blank to slip laterally toward and into the mold as the molding deformation of the raw material blank is carried out. Namely, as the upper and lower mold tools are pressed together and thereby deform the raw material blank from its initial flat planar configuration into a three-dimensionally molded contoured configuration, this deformation takes up additional material and thus inwardly pulls the surplus edge rim of the material, which is allowed to slip inwardly through the slip frame. In this regard, for example see U.S. Pat. No. 6,524,510, U.S. Pat. No. 6,136,415, U.S. Pat. No. 5,413,661, U.S. Pat. No. 5,076,880, etc.
The conventionally known apparatuses as described above suffer several disadvantages arising directly due to the use of the slip frame. Most importantly, the use of a slip frame necessarily requires the provision of a rather large surplus edge rim of the raw material protruding laterally beyond the edge of the mold. This surplus edge rim of the material represents waste that is ultimately cut or trimmed from the edge of the finished molded product. For large surface area products, the relative proportion of the edge rim waste is relatively small. However, the edge rim waste becomes gravely significant in connection with relatively small products or products that are relatively narrow but long. In general, the conventionally known methods and apparatuses require a surplus edge rim, and thus ultimately an edge rim waste, of at least 40 to 50 mm on each side of the mold. This is conventionally unavoidable because the conventional slip frame is spaced laterally by at least about 10 mm away from the outer edges of the mold, the slip frame itself typically has a width of at least about 25 mm, and a surplus rim edge protruding at least about 15 mm outwardly from the slip frame is typically left to allow for the slippage during molding as well as to allow a clamp frame or needle frame of a material transport mechanism to grasp the edges of the material. This gives an ultimate material waste of at least 40 to 50 mm on each side of the mold, i.e. on each side of the molded product. This can result in about 20% material waste when molding a typical motor vehicle door panel, for example. Especially when using high value raw materials, such as natural leather cover layers or the like, the amount of material waste becomes a significant cost factor and must be reduced to provide an economic advantage.
A further disadvantage of using a conventional slip frame is that the overall apparatus then takes up a lot of space, i.e. is very large due to the extra space required by the slip frames at the sides of the mold tools. The conventional arrangements thus often take up an unacceptably large space, regardless whether relatively small-area products or relatively large-area products are being produced. As a result, the overall molding system takes up a disproportionately large space and is especially very long in comparison to the length of the product being produced.